The present invention relates to a vehicle sun roof system, and in particular to a vehicle sun roof system provided with an improved slide mechanism for a moveable sun roof panel.
A vehicle sun roof system is typically provided with a moveable sun roof panel that can slide in a fore-and-aft direction to open and close an opening formed in a fixed roof panel of the vehicle. A pair of guide rails are provided in a lower part of the fixed roof panel on either side of the opening, and the moveable panel is provided with four sliders which are slidably engaged by the guide rails.
Because the moveable panel is supported solely by these sliders, to maximize the support rigidity of the moveable panel, it is preferable to attach the sliders to the front end and rear end of the moveable panel, and minimize the forward and rearward overhangs of the moveable panel that extend beyond the sliders.
However, the guide rails are required to be protected from moisture in order to ensure a smooth operation thereof, and the front end of each guide rail is required to be set back from the front edge of the opening by an appropriate distance. In particular, when the corners of the front end of the opening is rounded or is provided with a relatively large radius of curvature for aesthetic reasons, the front ends of the guide rails are required to be substantially set back from the front end of the opening in the roof panel. Modern automotive design is often such that the front window shield is strongly curved so that the front end of the opening in the roof has to be rounded accordingly.
In such a case, the front sliders are required to be set back from the front edge of the moveable panel to match the guide rails which are set back from the front end of the opening, and this results in a substantial front overhang of the moveable panel. Such an overhang is undesirable because the support structure has to be strengthened to ensure the required support rigidity. This is detrimental to compact, light-weight economical design of the vehicle sun roof system.
In such a guide structure, dimensional errors are inevitable between the guide rail and the slider, and it is customary to fit resilient shoes on the sliders so as to eliminate a play that may exist between the guide rail and the slider and ensure a smooth movement of the slider along the guide rail. For instance, Japanese utility model publication 5-29928 discloses a structure in which each slider shoe is provided with an inner wall portion which resiliently fits onto a stay member attached to a moveable panel, an outer wall portion which resiliently engages the guide slot and a space between the inner and outer wall portions to accommodate the resilient deformations of the inner and outer wall portions.
However, this arrangement requires a space between the inner and outer wall portions, and causes a vertical dimension of the guide structure to be increased. This is detrimental to the effort to minimize the vertical dimension of the sun roof system to provide a large head clearance in the passenger compartment of the vehicle without increasing the height of the roof panel.
In a sun roof system which is capable of both a slide open motion and a tilt up motion, it is necessary to prevent the fore-and-aft movement of the moveable panel while the moveable panel is anywhere between the fully closed position and a fully tilted up position. Japanese patent publication No. 05-23208 discloses a lock lever pivotally attached to a front slider via a laterally extending pin shaft, and provided with a front end which can selectively engage an opening provided in the guide rail.
According to this conventional arrangement, when the rear end of the moveable panel tilts down as a step preliminary to sliding rearward, the moveable panel pushes down the rear end of the lock lever, causing the front end to be disengaged from the opening and allowing the moveable panel to slide rearward. Conversely, when the moveable panel slides forward and approaches its fully closed position, the rear end of the moveable panel is tilted up and causes the lock lever to engage the opening. However, because the front end of the lock lever consists of a simple, downwardly extending projection, there was a concern that the lock lever may be inadvertently disengage from the opening, particularly when the rear end of the moveable panel tilts down and the projection of the lock lever tilts rearward as a result.
According to a sun roof system of an inner slide type such as the one disclosed in Japanese patent laid open publication No. 03-121926, the moveable panel is stowed in a space defined under the fixed roof panel behind the opening defined in the fixed roof panel when it is slid rearward toward its fully open position. Therefore, when moving the moveable panel rearward from its fully closed position, it is necessary to tilt down the rear end of the moveable panel, and it is typically accomplished by guiding a pin shaft laterally extending from a stay member depending from the moveable panel along a vertical slot for tilting the rear end of the moveable panel and along a substantially horizontal path for sliding the moveable pane rearward.
Conventionally, the tilt down motion was accomplished by dropping the laterally extending pin shaft into the horizontal guide slot via an opening passed through an opening formed in an upper wall of the guide rail defining the guide slot. Therefore, the transition from the tilt down motion to the slide motion was not effected in as smooth a fashion as desired, and a striking noise may even be produced when the laterally extending pin shift drops into the guide slot.
In view of such problems of the prior art, a primary object of the present invention is to provide an improved sun roof system having a favorable slide guide mechanism that ensures a smooth movement of the moveable panel and a high support rigidity for the moveable panel at the same time.
A second object of the present invention is to provide an improved sun roof system which can operate smoothly even when a camber or a warping is present in the guide rail.
A third object of the present invention is to provide an improved sun roof system which can operate smoothly and requires a small vertical dimension.
A fourth object of the present invention is to provide an improved sun roof system which is capable of both a tilt up motion and a slide motion in a highly reliable manner.
A fifth object of the present invention is to provide an improved sun roof system which allows the moveable panel to be moved into a space defined under the fixed roof panel immediately behind the opening in a highly smooth and noiseless manner.
According to the present invention, such objects can be accomplished by providing a vehicle sun roof system, comprising: a fixed roof panel defining an opening having a rounded shape; a pair of guide rails extending on the fixed roof panel in a fore-and-aft direction along either side of the opening; and a moveable panel having a pair of sliders on each side thereof, the sliders being slidably engaged by a corresponding one of the guide rails one in the front and the other in the rear; each of the front sliders being provided with at least three laterally extending slide shoes including a front inboard slide shoe, a rear inboard slide shoe and a front outboard slide shoe located intermediate between the inboard slide shoes with respect to a fore-and-aft direction, the guide rail being provided with an inboard side defining an inboard guide slot and an outboard side defining an outboard guide slot adapted to receive the corresponding slide shoes, the outboard side of the guide rail being provided with a front end which is rearwardly offset from that of the inboard side of the guide rail.
Thus, the front end of each guide rail is advanced as much as possible without increasing the exposure of such parts to the moisture that may drip from the fixed roof panel and/or moveable panel by taking into account the rounded shape of the opening in the fixed roof panel. Therefore, the position of the front sliders for the moveable panel can be advanced by a corresponding degree, and the overhang of the moveable panel from the front sliders can be minimized. This contributes to the increase in the mechanical rigidity and strength of the front part of the moveable panel. Each of the front sliders may further comprise a rear outboard slide shoe provided on an outboard side of the front slider at a substantially same fore-and-aft position as the rear inboard slide shoe to ensure a laterally balanced support for the front slider.
As there are three slide shoes which are arranged along a longitudinal line, a camber in the guide rail or a convex surface of the guide rail as seen from a side may prevent a smooth movement of the corresponding front slider. It can be avoided if the front outboard slide shoe is provided with a resiliently deformable lower surface. Such a deformable lower surface can be accomplished if the front outboard slide shoe is fitted on a tongue member extending laterally from a main part of the front slider in an outboard direction, and a recess is formed in a bottom surface of the tongue member to provide a flexibility to a part of the outboard slide shoe extending over the recess. According to this arrangement, the deformation of the wall of the slide shoe can be accommodated by the recess provided in the corresponding part of the slider which typically consists of a tongue member, and the overall thickness of the shoe can be minimized.
If the guide rail is provided with a concave surface as seen from a side, a smooth movement of the corresponding front slider can be ensured if the front inboard slide shoe and rear inboard slide show are each provided with a resiliently deformable upper surface. Again, such a deformable upper surface can be accomplished if each of the front and rear inboard slide shoes is fitted on a tongue member extending laterally from a main part of the front slider in an inboard direction, and a recess is formed in a top surface of the tongue member to provide a resiliency to a part of the inboard slide shoe extending over the recess.
The flexibility in the upper and/or lower surfaces of the slide shoes is effective in removing a play for the moveable panel in the vertical direction. A play in the lateral direction for the moveable panel can be removed if at least one of the slide shoes is provided with a resilient portion on a side end thereof for resiliently engaging a bottom surface of a corresponding one of the guide slots.
According to a preferred embodiment of the present invention, the sun roof system further comprises a lock lever pivotally supported by one of the front sliders via a laterally extending pin shaft and provided with a front end having a downwardly depending projection, and an engagement portion provided in a part of the corresponding guide rail for engaging the projection in a fully closed state of the moveable panel, the lock lever being provided with a cam surface for rocking the locking lever out of engaging from the engagement portion when a rear end of the moveable panel is tilted down as a step preliminary to a rearward slide motion, at least one of the engagement portion and the projection being provided with an overhang for securely engaging the projection with the engagement portion. The engagement portion may include an opening formed in the guide rail.
Because of the angle of the projection is determined such that the projection engages the opening with an overhang portion thereof, the engagement between the projection and opening can be ensured when the moveable panel is subjected to a rearward force but is required to be prevented from a rearward movement. Thus, a secure engagement between the moveable panel and the fixed roof panel can be ensured when such an engagement is needed. This is particularly significant when the sun roof system is adapted to both a slide motion and a tilt up motion because the tilt up motion is typically effected by a rearward force acting on a suitable cam mechanism, and it is essential that during the tilt up motion the moveable panel is prevented from moving rearwardly. Thus, a secure engagement between the moveable panel and the fixed roof panel can be ensured when the moveable panel is fully closed and being tilted up.
For the moveable panel to be able to move rearwardly, it needs to tilt down so that it may be stowed in a space defined under the fixed roof panel immediately behind the opening. Such a motion can be accomplished by a corresponding guide slot formed in the guide rail. According to a preferred embodiment of the present invention, the guide rail includes a vertical slot for guiding a laterally extending pin shaft attached to a rear part of the moveable panel to tilt down a rear end of the moveable panel and a horizontal slot extending rearward from a lower part of the vertical slot to accommodate a rearward sliding movement of the moveable panel, the guide rail including a section made of a separate member which defines at least a part of the vertical slot and a part of the horizontal slot connected to the lower part of the vertical slot. To prevent noises when the laterally extending pin shaft is guided by such a guide slot, the separate member preferably includes a part made of plastic material.